1. Field of the Invention
The present invention relates to optical reflectors, and light modulators, more particularly, to wide-angle optical retroreflectors that can provide light intensity modulation and can be coupled to typical optical components.
2. The Prior Art
A retroreflector is an optical device that reflects an incident light beam from any direction back along its original path without need for optical alignment. A well-known retroreflector is the cube corner type retroreflector or hollow cavity retroreflector. A light intensity modulator is a device that can change its light transmission through applying electric signals on the device. A mere mechanical combination of a retroreflector and a light modulator can produce a retroreflecting modulator. However, for many important applications, such a simplistic combination can have only limited use because of a number of deficiencies. The most important are limited field of view and a poor performance in connection with the primitive structure.
U.S. Pat. No. 4,777,660, issued to Gould, discloses a retroreflective optical communication system. This system employs a mechanical combination of a cube-corner retroreflector and light modulator based on gas Stark effect cells. Such system is limited to work only with CO.sub.2 lasers and gas cells.